30482399232domain: NAppears in sequencesa(n)*a(n+3) - a(n+1)*a(n+2) = 2^n, given a(0)=1, a(1)=1, a(2)=3.at n=30A080878Expansion of (1-3*x)/(1 - 6*x + 4*x^2).at n=15A098648